The present invention relates generally to the transmission of data between a data processing system and input/output devices, and relates in particular to a Universal Serial Bus (USB) with a wireless communication hub for transmitting data between a data processing system and input/output devices.
In 1995, several of the leading companies in the field of data processing developed an external expansion bus, which makes connecting peripherals to a personal computer (PC) as easy as hooking up a telephone to a wall-jack. The goals driving the development were ease-of-use and low cost. The development included the following specifications: PC host controller hardware and software, robust connectors and cable assemblies, peripheral friendly master-slave protocols, and expandability through multi-port hubs.
Today, the resulting Universal Serial Bus (USB) is enjoying tremendous success in the marketplace with most peripheral vendors around the globe developing products to the USB specification. Virtually all new PCs come with one or more USB ports. In fact, the USB has become a key enabler of the Easy PC Initiative led by Intel Corporation and Microsoft Corporation to make PCs easier to use. The effort was initiated based upon the recognition that users desired that connection of external components to of PCs be simplified in a manner that does not sacrifice connectivity or expandability. The USB is one of the key technologies developed to satisfy the user""s needs.
The motivation for the Universal Serial Bus comes from three interrelated considerations.
(1) Connection of the PC to the Telephone
It is well understood that the merging of computing and communication will be the basis for the next generation of productivity applications. The movement of machine-oriented and human-oriented data types from one location or environment to another depends on ubiquitous and cheap connectivity. Unfortunately, the computing and communication industries have evolved independently. The Universal Serial Bus provides a ubiquitous link that can be used across a wide range of PC-to-telephone interconnects.
(2) Ease of Use
The lack of flexibility in reconfiguring PCs has been acknowledged as the Achilles heel to further deployment of PCs. The combination of user friendly graphical interfaces and the hardware and software mechanisms associated with new generation bus architectures like peripheral component interconnect (PCI), plug-and play industry standard architecture (PnP ISA), and Personal Computer Memory Card International Association (PCMCIA) has made computers less confrontational and easier to reconfigure. However, from the end user point of view, the PC input/output (I/O) interfaces such as serial/parallel ports, keyboard/mouse/joystick interfaces, etc., do not have the attributes of plug-and-play.
(3) Port Expansion
The addition of external peripherals continues to be constrained by port availability. The lack of a bi-directional, low-cost, low-to-mid speed peripheral bus has retarded the creative proliferation of peripherals such as telephone/fax/modem adapters, answering machines, scanners, personal digital assistants (PDAs), keyboards, mice, etc. Existing interconnects are optimized for one or two products. As each new function or capability is added to the PC, a new interface is defined to address the need. The Universal Serial Bus is the answer to connectivity for the PC architecture. It is a fast, bi-directional, low-cost, dynamically attachable serial interface that is consistent with the requirements of the PC platform of today and tomorrow.
When the input/output, devices are attached to the USB, the host software provides a uniform view for all the I/O subsystem. In particular, the host software manages the dynamic attach and detach of the peripherals to the USB. This phase, called enumeration, involves communicating with the peripheral to discover the identity of a device driver that it should load, if the driver is not already loaded. A unique address used for run-time data transfers is assigned to each peripheral during enumeration. During run-time, the host PC initiates transactions to specific peripherals, and each peripheral accepts its transactions and responds accordingly.
An essential part of the USB is a hub which provides managed power to attached peripherals. The hub recognizes dynamic attachment of a peripheral. A newly attached hub will be assigned a unique address, and hubs may be cascaded up to five levels deep. During run-time, a hub operates as a bi-directional repeater and will repeat USB signals as required on upstream (towards the host) and downstream (towards the device) cables. The hub also monitors the signals and handles transactions addressed to itself. All other transactions are repeated to attached devices. A hub supports both 12 Mb/s (full-speed) and 1.5 Mbs (low-speed) peripherals.
In spite of the important advantages offered by the USB, in particular the possibility for the PC to support simultaneous attachment of multiple I/O devices, the use of the USB is at present limited to devices which are located in the same room or office. Furthermore, there is only one host computer on a USB. The USB interface to the host computer is referred to the host controller, which is implemented as a combination of hardware and software. Therefore, it is not possible to connect a second computer to the USB and to make it host for controlling the system in place of the first host computer without making hardware and software changes in the system.
Accordingly, one purpose of the invention is to provide a Universal Serial Bus with wireless communication hubs enabling the input/output devices connected thereto to be located in a room or office different from the host computer location.
Another purpose of the invention is to connect input/output (I/O) devices to a first host computer via wireless communication hubs and thereafter enable a second host computer to assume control of the I/O devices.
The invention relates to a Universal Serial Bus (USB) with two wireless communication hubs (USB hubs). One of these hubs is connected to a first host computer, and both USB hubs are connected to a plurality of I/O devices. Each USB hub includes a wireless adapter and an antenna connected to the wireless adapter. The wireless adapter of each USB hub comprises a transmitting/receiving unit for transmitting data via the antenna to the wireless adapter of the other USB hub or receiving data via the antenna from the wireless adapter of the other USB hub. The wireless adapter also comprises a wireless dual port, which is automatically configured upstream or downstream when the first host computer is connected to one of the USB hubs.
The above as well as additional purposes, features, and advantages of an illustrative embodiment will become apparent in the following detailed written description.